Deactive imap account

Hi, I have 3 imap accounts and want to deactivate one of them. How can I do this ?

By deactivate I mean I still want to keep the imap account and it’s emails but have it not sync’d.

This is not yet a feature, although it has been requested. Voting for it will increase the likelihood it’s implemented.

With IMAP the mail’s are kept on the server. If you want to keep the emails but not the account, you have to copy the email to a local folder (or a folder in another account), then delete the account. Keeping a “last seen” cache copy of the IMAP mails is, in my opinion, prone to breaking, but I’m not a developer.